// Copyright 2016 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef V8_INSPECTOR_STRING_16_H_
#define V8_INSPECTOR_STRING_16_H_

#include <stdint.h>
#include <cctype>
#include <climits>
#include <cstring>
#include <string>
#include <vector>

#include "src/base/compiler-specific.h"

namespace v8_inspector {

using UChar = uint16_t;

class String16 {
public:
    static const size_t kNotFound = static_cast<size_t>(-1);

    String16() = default;
    String16(const String16&) /*V8_NOEXCEPT*/ = default;
    String16(String16&&) /*V8_NOEXCEPT*/ = default;
    String16(const UChar* characters, size_t size);
    String16(const UChar* characters); // NOLINT(runtime/explicit)
    String16(const char* characters); // NOLINT(runtime/explicit)
    String16(const char* characters, size_t size);
    explicit String16(const std::basic_string<UChar>& impl);

    String16& operator=(const String16&) /*V8_NOEXCEPT*/ = default;
    String16& operator=(String16&&) /*V8_NOEXCEPT*/ = default;

    static String16 fromInteger(int);
    static String16 fromInteger(size_t);
    static String16 fromDouble(double);
    static String16 fromDouble(double, int precision);

    int64_t toInteger64(bool* ok = nullptr) const;
    int toInteger(bool* ok = nullptr) const;
    String16 stripWhiteSpace() const;
    const UChar* characters16() const { return m_impl.c_str(); }
    size_t length() const { return m_impl.length(); }
    bool isEmpty() const { return !m_impl.length(); }
    UChar operator[](size_t index) const { return m_impl[index]; }
    String16 substring(size_t pos, size_t len = UINT_MAX) const
    {
        return String16(m_impl.substr(pos, len));
    }
    size_t find(const String16& str, size_t start = 0) const
    {
        return m_impl.find(str.m_impl, start);
    }
    size_t reverseFind(const String16& str, size_t start = UINT_MAX) const
    {
        return m_impl.rfind(str.m_impl, start);
    }
    size_t find(UChar c, size_t start = 0) const { return m_impl.find(c, start); }
    size_t reverseFind(UChar c, size_t start = UINT_MAX) const
    {
        return m_impl.rfind(c, start);
    }
    void swap(String16& other)
    {
        m_impl.swap(other.m_impl);
        std::swap(hash_code, other.hash_code);
    }

    // Convenience methods.
    std::string utf8() const;
    static String16 fromUTF8(const char* stringStart, size_t length);

    std::size_t hash() const
    {
        if (!hash_code) {
            for (char c : m_impl)
                hash_code = 31 * hash_code + c;
            // Map hash code 0 to 1. This double the number of hash collisions for 1,
            // but avoids recomputing the hash code.
            if (!hash_code)
                ++hash_code;
        }
        return hash_code;
    }

    inline bool operator==(const String16& other) const
    {
        return m_impl == other.m_impl;
    }
    inline bool operator<(const String16& other) const
    {
        return m_impl < other.m_impl;
    }
    inline bool operator!=(const String16& other) const
    {
        return m_impl != other.m_impl;
    }
    inline String16 operator+(const String16& other) const
    {
        return String16(m_impl + other.m_impl);
    }

    // Defined later, since it uses the String16Builder.
    template <typename... T>
    static String16 concat(T... args);

private:
    std::basic_string<UChar> m_impl;
    mutable std::size_t hash_code = 0;
};

inline String16 operator+(const char* a, const String16& b)
{
    return String16(a) + b;
}

class String16Builder {
public:
    String16Builder();
    void append(const String16&);
    void append(UChar);
    void append(char);
    void append(const UChar*, size_t);
    void append(const char*, size_t);
    void appendNumber(int);
    void appendNumber(size_t);
    void appendUnsignedAsHex(uint64_t);
    void appendUnsignedAsHex(uint32_t);
    String16 toString();
    void reserveCapacity(size_t);

    template <typename T, typename... R>
    void appendAll(T first, R... rest)
    {
        append(first);
        appendAll(rest...);
    }
    void appendAll() { }

private:
    std::vector<UChar> m_buffer;
};

template <typename... T>
String16 String16::concat(T... args)
{
    String16Builder builder;
    builder.appendAll(args...);
    return builder.toString();
}

} // namespace v8_inspector

#if !defined(__APPLE__) || defined(_LIBCPP_VERSION)

namespace std {
template <>
struct hash<v8_inspector::String16> {
    std::size_t operator()(const v8_inspector::String16& string) const
    {
        return string.hash();
    }
};

} // namespace std

#endif // !defined(__APPLE__) || defined(_LIBCPP_VERSION)

#endif // V8_INSPECTOR_STRING_16_H_
